Regulator for mixed-pressure turbines.



H VV.KIESER. REGULATOR FOR MIXED PRESSURE TURBINES.

APPLICATION FILED OUT. 6, 1914.

1,121,020, Patented Dec. "15, 1914.

vvknessesz Inventofi Walter Kieser,

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pressure valves UNITED STATES rarrnn'r OFFICE.

WALTER KIESER, OF GHARLOTTENIBURG, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

REGULATOR FOR MIXED-PRESSURE TURBINES.

Application filed Qctober G 1914. Serial No. 865,250.

To all whom it may concern Be. it known that I, WALTER .Knasna, a citizen of the Swiss Republic, residing at Charlottenburg, Germany, have invented certain new and useful Improvements in Regulators for Mixed-Pressure Turbines, of e which the following is a specification.

This invention relates to elastic-fluid turbines driven primarily by low pressure steam, but provided with high pressure valve mechanism, and a governing appartus which admits high pressure steam thereto when the supply of low pressure steam becomes inadequate to carry the load. These mixed-pressure machines, as they are sometimes called, have been provided not only with a speed governor, but with a pressureresponsive device which is influenced by the variations of the low pressure steam and acts to open the low pressure valve and close the high pressure valves upon an increase in the tension of the low pressure steam, or to operate the valves in the opposite manner when the pressure falls. The use of a common pressure regulator for the high and low has, however, various inherent disadvantages. For example, when the lowv pressure steam comes from the exhaust of a hoisting engine, or one driving a rolling mill, the supply is very intermittent, so that great variations of pressure occur in the accumulator which is usually interposed between such an engine and the lowpressure turbine. The result is that when the supply of low pressure steam becomes reduced for a short time, the operation of the turbine shifts to that of a mixed-pressure machine, but if in the next instant the exhaust steam renews its supply the machine must be changed again to pure exhaust operation. This keeps the two steam valves in continuous movement. But if the pressure regulator is made sufficiently insensitive to avoid these constant changes, then 'variations in the output of the turbine will result, so that its speed governor will fluctuate continuously and a uniform number of revo-,

lutions cannot be maintained. This difliculty is avoided by the present invention, in which the low pressure valve and the high pressure valve are supplied with separate and independent pressure regulators responsive to pressure variations in the low pressure supply of steam; the regulator for the high pressure valve being more sensitive to smallfiuctuations in pressure than the regulator for the low pressure valve; By .this

Specification of Letters Patent. Patented De 15 1914,

arrangement a ontinuous oscillation of the 1 w?pressure-valveis prevented, and moreover, the sllght variations in the supply of energy are equalized by suitable movements of the high pressure valve, so that in spite of variations in the supply of low pressure steam, the number of revolutions will be kept constant without the interposition of the speed governor; which operates only when variations of load occur.

An embodiment of my invention is illustrated diagrammatically in the accompanying drawing.

The low pressure steam valve 1 is actuated by a motor 2, whose supply of motive fluid coming through a pipe 3 is controlled by a pilot valve 4. The stem 5 of this valve is pivoted to a lever 6, one end of which is pivotally connected to a follow-up lever 7 whose other end is pivoted to the end of the piston rod 8 of the motor 2. The other end of the lever 6 is ivoted to a verticall movable member sucii as a plunger 9 wor ing in a guide 10 and urged upwardly by a spring 11; a stop 12 limiting the upward movement. The high pressure steam valve 13 is provided with a similar motor 14, pilot valve 15, levers 16 and 17 and plunger 18. In this case, however, the plunger is urged d o'wnwardly by its spring 19 and the stop 20 limits the downward movement. 7' Connecting the lower ends of the two plungers is a floating lever21 whose middle point is operatively connected with the speed governor 22, in such a manner that upon a decrease of speed the floating lever will be lifted, and vice versa.

The cylinder 23 of a pressure-responsive device has a movable abutment 24 urged downwardly by a spring 25 against the pressure of the low pressure steam which is admitted under it by a conduit 26 having a throttle valve 27 The abutment 24: is con:

. urges the abutment downward. A stronger spring 34, coiled between the head of the low pressure valve cylinder 32 and a washer at the lower end of a sr-rmv-threaded adjusting rod 35. is held in readiness to be picked up by the movable abutment 31 after it has risen a short distance under a heavy increase in fluid pressure beneath it. A rod 36 connects the abutment 31 with an intermediate point on the lever 17.

The operation is as follows: Assume that the turbine is operating on low pressure steam and that the load increases. The lessened speed causes the governor 22 to push up the floating lever 21. Owing to the resistance of the spring 19 the lever will fulcrum on the plunger 18 and will force up the plunger 9. relieving the compression of the spring 11 and lifting the lever 6 and the pilot valve This admits fluid pressure under the piston of the motor 2 which opens the low pressure valve 1. to admit steam more freely to restore the speed of the turbine. When the valve 1 has been opened to its fullest extent. the stop 12 abuts against the stationary guide 10. and if the turbine is still unable to carry its load. the further upward movement of the floating lever 21 by the speed governor causes said lever to fulcrum at the lower end of the plunger 9 and push up the plunger 18, compressing the spring 19 and lifting one end of the lever 17. This lever fulcrums on the rod 36 and depresses the lever 16 and the pilot valve 15, thereby admitting fluid pressure under the piston of the motor 14 and opening the high pressure valve 13 to admit high pressure steam to the turbine to enable it to carry the increased load. The machine is now operating as a mixed-pressure turbine, using all the low pressure steam available. and as much high pressure steam as may be necessary to give the power required. If, now, the pressure of the low pressure steam decreases from any reason, the abutment 2 1 of the low pressure regulator will descend, and cause the pilot valve 4 to admit fluid pressure above the piston of'the motor 2 to cause it to close the 1. On the other hand, the descentof the abutment 31 in the high pressure regulator will cause the pilot valve 15 to admit fluid pressure under the piston of its motor and thereby open the high pressure valve 13 still wider to make up for the loss of low pressure steam. Now, while the machine is operating as a mixed-pressure turbine assume that a sudden increase in the supply of low pressure steam occurs, but only for a short time. The lighter spring '33 of the high pressure regulator will yield more quickly than the heavier spring 23 of the low pressure regulator, so that the levers l7 and 16 and the pilot valve 15 will be quickly lifted, admitting fluid pressure on top of the iston in the motor 14 and closiiig thehig pressure valve 13. This prevents any fluctuation in speed from the sudden increase in the low pressure steam. This movement of the abutment 31 is not great, because it very soon picks up the auxiliary spring 3 1 and its movement is then retarded; both regulators then responding about equally to any further increase in pressure of the low pressure steam. But the light spring enables the high pressure regulator to respond so quickly that the speed governor is not called upon to meet conditions arising from sudden changes in the low pressure supply. All that the speed governor has to do is to open or close the valves in case of an increase or decrease of load. I

By means of the throttle valves 27, 30 the two pressure regulators are rendered quite independent of each other and can be regulated to give more or less rapid response to pressure changes.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. A regulator for mixed-pressure turbines, comprising a speed governor, a floating lever operatively connected thereto, members connected to the ends of said lever and yielding in opposite directions, high and low pressure valves, and operative means connected respectively between said valves and said yielding members.

2. A bines, comprising a s eed governor, a floating lever operative y 1 connected thereto, plungers pivoted to the ends of said lever, springs urging said plungers in opposite directions, high and'low pressure valves, and a system of levers and a motor between each valve and its respective plunger.

3. A regulator for mixed-pressure turbines, comprising a speed governor, a fioating lever operatively connected thereto, stationary guides, plungers therein pivoted to the ends of said lever and having stops, springs urging said plungers in opposite directions, and high and low pressure valves operatively connected with said plungers.

4. A regulator for mixed-pressure turbines, comprising a speed governor, high and low pressure valves, and a separate pressure regulator for each valve, the one for the high pressure valve being the more sensitive.

5. A regulator for mixed-pressure turbines, comprising a speed governor, high and low pressure valves, a pressure regu- Itegulator for mixed-pressure tut and low pressure valves, a separate pressure regulator for each valve, and a lighter spring for the high ressure valve regulator.

7. A regulator bines, comprising a speed governor, high and low pressure valves, a separate pressure regulator for each valve, and two springs for the high pressure valve regulator, one of which is light and is in constant use, While the other c n1esinto play only when there isor mixed-pressure tura' heavy increase in the supply of low pressure steam. Y

8. A regulator tor mixed-pressure turbines, comprising high and low pressure valves, a separate pressure regulator for each valve, a conduit conveying low pressure steam to each regulator, a throttle valve for each regulator controlling the fiow of steam thereto, and a speed governor cooperating with the pressure regulators.

In witness whereof, I have hereunto set my-hand this tenth day. of September, 1914.

WALTER KIESER.

WVitnesses:

EVERET KELLER, WILLY NEUMANN. 

